refactor: revert autoStart and onDetect. See changelog for more

+## 5.1.0
+
+This updates reverts a few breaking changes made in v5.0.0 in order to keep things simple.
+
+* The `onDetect` method has been reinstated in the `MobileScanner` widget, but is nullable. You can
+still listen to `MobileScannerController.barcodes` directly by passing null to this parameter.
+* The `autoStart` attribute has been reinstated in the `MobileScannerController` and defaults to true. However, if you want
+to control which camera is used on start, or you want to manage the lifecycle yourself, you should set
+autoStart to false and manually call `MobileScannerController.start({CameraFacing? cameraDirection})`.
+* The `controller` is no longer required in the `MobileScanner` widget. However if provided, the user should take care 
+of disposing it.
+* [Android] Revert Gradle 8 back to Gradle 7, to be inline with most Flutter plugins and prevent build issues.
+* [Android] Revert Kotlin back from 1.9 to 1.7 to be inline with most Flutter plugins. Special 1.9 functionality
+has been refactored to be compatible with 1.7.
+
+
 ## 5.0.2
 
 Bugs fixed:

@@ -7,6 +7,10 @@
 
 A universal scanner for Flutter based on MLKit. Uses CameraX on Android and AVFoundation on iOS.
 
+## Breaking Changes V5.0.0
+
+Version 5.0.0 brings some breaking changes. Please see the changelog for an overview.
+
 ## Features Supported
 
 See the example app for detailed implementation information.

@@ -13,7 +13,8 @@ class BarcodeScannerPageView extends StatefulWidget {
 }
 
 class _BarcodeScannerPageViewState extends State<BarcodeScannerPageView> {
-  final MobileScannerController controller = MobileScannerController();
+  final MobileScannerController controller =
+      MobileScannerController(autoStart: false);
 
   final PageController pageController = PageController();
 

+import 'dart:async';
+
+import 'package:flutter/material.dart';
+import 'package:mobile_scanner/mobile_scanner.dart';
+import 'package:mobile_scanner_example/scanner_button_widgets.dart';
+import 'package:mobile_scanner_example/scanner_error_widget.dart';
+
+class BarcodeScannerSimple extends StatefulWidget {
+  const BarcodeScannerSimple({super.key});
+
+  @override
+  State<BarcodeScannerSimple> createState() => _BarcodeScannerSimpleState();
+}
+
+class _BarcodeScannerSimpleState extends State<BarcodeScannerSimple> {
+  Barcode? _barcode;
+
+  Widget _buildBarcode(Barcode? value) {
+    if (value == null) {
+      return const Text(
+        'Scan something!',
+        overflow: TextOverflow.fade,
+        style: TextStyle(color: Colors.white),
+      );
+    }
+
+    return Text(
+      value.displayValue ?? 'No display value.',
+      overflow: TextOverflow.fade,
+      style: const TextStyle(color: Colors.white),
+    );
+  }
+
+  void _handleBarcode(BarcodeCapture barcodes) {
+    if (mounted) {
+      setState(() {
+        _barcode = barcodes.barcodes.firstOrNull;
+      });
+    }
+  }
+
+  @override
+  Widget build(BuildContext context) {
+    return Scaffold(
+      appBar: AppBar(title: const Text('Simple scanner')),
+      backgroundColor: Colors.black,
+      body: Stack(
+        children: [
+          MobileScanner(
+            onDetect: _handleBarcode,
+          ),
+          Align(
+            alignment: Alignment.bottomCenter,
+            child: Container(
+              alignment: Alignment.bottomCenter,
+              height: 100,
+              color: Colors.black.withOpacity(0.4),
+              child: Row(
+                mainAxisAlignment: MainAxisAlignment.spaceEvenly,
+                children: [
+                  Expanded(child: Center(child: _buildBarcode(_barcode))),
+                ],
+              ),
+            ),
+          ),
+        ],
+      ),
+    );
+  }
+}

@@ -3,6 +3,7 @@ import 'package:mobile_scanner_example/barcode_scanner_controller.dart';
 import 'package:mobile_scanner_example/barcode_scanner_listview.dart';
 import 'package:mobile_scanner_example/barcode_scanner_pageview.dart';
 import 'package:mobile_scanner_example/barcode_scanner_returning_image.dart';
+import 'package:mobile_scanner_example/barcode_scanner_simple.dart';
 import 'package:mobile_scanner_example/barcode_scanner_window.dart';
 import 'package:mobile_scanner_example/barcode_scanner_zoom.dart';
 import 'package:mobile_scanner_example/mobile_scanner_overlay.dart';
@@ -31,6 +32,16 @@ class MyHome extends StatelessWidget {
               onPressed: () {
                 Navigator.of(context).push(
                   MaterialPageRoute(
+                    builder: (context) => const BarcodeScannerSimple(),
+                  ),
+                );
+              },
+              child: const Text('MobileScanner Simple'),
+            ),
+            ElevatedButton(
+              onPressed: () {
+                Navigator.of(context).push(
+                  MaterialPageRoute(
                     builder: (context) => const BarcodeScannerListView(),
                   ),
                 );

@@ -4,6 +4,7 @@ import 'package:flutter/material.dart';
 import 'package:mobile_scanner/src/mobile_scanner_controller.dart';
 import 'package:mobile_scanner/src/mobile_scanner_exception.dart';
 import 'package:mobile_scanner/src/mobile_scanner_platform_interface.dart';
+import 'package:mobile_scanner/src/objects/barcode_capture.dart';
 import 'package:mobile_scanner/src/objects/mobile_scanner_state.dart';
 import 'package:mobile_scanner/src/scan_window_calculation.dart';
 
@@ -18,7 +19,8 @@ typedef MobileScannerErrorBuilder = Widget Function(
 class MobileScanner extends StatefulWidget {
   /// Create a new [MobileScanner] using the provided [controller].
   const MobileScanner({
-    required this.controller,
+    this.controller,
+    this.onDetect,
     this.fit = BoxFit.cover,
     this.errorBuilder,
     this.overlayBuilder,
@@ -29,7 +31,11 @@ class MobileScanner extends StatefulWidget {
   });
 
   /// The controller for the camera preview.
-  final MobileScannerController controller;
+  final MobileScannerController? controller;
+
+  /// The function that signals when new codes were detected by the [controller].
+  /// If null, use the contrller.barcodes stream directly to capture barcodes.
+  final void Function(BarcodeCapture barcodes)? onDetect;
 
   /// The error builder for the camera preview.
   ///
@@ -113,6 +119,7 @@ class MobileScanner extends StatefulWidget {
 }
 
 class _MobileScannerState extends State<MobileScanner> {
+  late final controller = widget.controller ?? MobileScannerController();
   /// The current scan window.
   Rect? scanWindow;
 
@@ -139,7 +146,7 @@ class _MobileScannerState extends State<MobileScanner> {
     if (scanWindow == null) {
       scanWindow = newScanWindow;
 
-      unawaited(widget.controller.updateScanWindow(scanWindow));
+      unawaited(controller.updateScanWindow(scanWindow));
 
       return;
     }
@@ -154,7 +161,7 @@ class _MobileScannerState extends State<MobileScanner> {
     if (widget.scanWindowUpdateThreshold == 0.0) {
       scanWindow = newScanWindow;
 
-      unawaited(widget.controller.updateScanWindow(scanWindow));
+      unawaited(controller.updateScanWindow(scanWindow));
 
       return;
     }
@@ -167,14 +174,14 @@ class _MobileScannerState extends State<MobileScanner> {
         dy >= widget.scanWindowUpdateThreshold) {
       scanWindow = newScanWindow;
 
-      unawaited(widget.controller.updateScanWindow(scanWindow));
+      unawaited(controller.updateScanWindow(scanWindow));
     }
   }
 
   @override
   Widget build(BuildContext context) {
     return ValueListenableBuilder<MobileScannerState>(
-      valueListenable: widget.controller,
+      valueListenable: controller,
       builder: (BuildContext context, MobileScannerState value, Widget? child) {
         if (!value.isInitialized) {
           const Widget defaultPlaceholder = ColoredBox(color: Colors.black);
@@ -234,10 +241,36 @@ class _MobileScannerState extends State<MobileScanner> {
     );
   }
 
+  StreamSubscription? barcodeSubscription;
+
+  @override
+  void initState() {
+    if (widget.onDetect != null) {
+      barcodeSubscription = controller.barcodes.listen(widget.onDetect);
+    }
+    if (controller.autoStart) {
+      controller.start();
+    }
+    super.initState();
+  }
+
   @override
   void dispose() {
     super.dispose();
+    if (barcodeSubscription != null) {
+      barcodeSubscription!.cancel();
+      barcodeSubscription = null;
+    }
+
+    if (controller.autoStart) {
+      controller.stop();
+    }
     // When this widget is unmounted, reset the scan window.
-    unawaited(widget.controller.updateScanWindow(null));
+    unawaited(controller.updateScanWindow(null));
+
+    // Dispose default controller if not provided by user
+    if (widget.controller == null) {
+      controller.dispose();
+    }
   }
 }

@@ -17,6 +17,7 @@ import 'package:mobile_scanner/src/objects/start_options.dart';
 class MobileScannerController extends ValueNotifier<MobileScannerState> {
   /// Construct a new [MobileScannerController] instance.
   MobileScannerController({
+    this.autoStart = true,
     this.cameraResolution,
     this.detectionSpeed = DetectionSpeed.normal,
     int detectionTimeoutMs = 250,
@@ -47,6 +48,9 @@ class MobileScannerController extends ValueNotifier<MobileScannerState> {
   /// Currently only supported on Android.
   final Size? cameraResolution;
 
+  /// Automatically start the scanner on initialization.
+  final bool autoStart;
+
   /// The detection speed for the scanner.
   ///
   /// Defaults to [DetectionSpeed.normal].

 name: mobile_scanner
 description: A universal barcode and QR code scanner for Flutter based on MLKit. Uses CameraX on Android, AVFoundation on iOS and Apple Vision & AVFoundation on macOS.
-version: 5.0.2
+version: 5.1.0
 repository: https://github.com/juliansteenbakker/mobile_scanner
 
 screenshots: